<template>
    <div>
    <div class="pagination">
      <button :disabled="pageNo==1" @click="$emit('getPageNo',pageNo-1)">上一页</button>
      <button v-if="pageNum.start!=1" @click="$emit('getPageNo',1)" :class="{active:pageNo==1}">1</button>
     
      <button v-if="pageNum.start>2">···</button>
  
      <button v-for="(page,index) in pageNum.end" :key="index" v-show="page>=pageNum.start" 
        @click="$emit('getPageNo',page)" :class="{active:pageNo==page}">
        {{page}}</button>
     
      
      <button v-if="pageNum.end<totalPage-1">···</button>
      <button v-if="pageNum.end!=totalPage" @click="$emit('getPageNo',totalPage)" :class="{active:pageNo==totalPage}">{{totalPage}}</button>
      <button :disabled="pageNo==totalPage" @click="$emit('getPageNo',pageNo+1)">下一页</button>
      
      <button style="margin-left: 30px">共 {{total}} 条</button>
    </div>
  
  </div>
  </template>
  
  <script>
    export default {
      name: "Pagination",
      props:['pageNo',"pageSize","total","continues"],
      computed:{
        totalPage(){
          return Math.ceil(this.total/this.pageSize)
        },

        pageNum(){
          let start=0;
          let end=0;
          if (this.total<this.continues){
            start=1;
            end=this.totalPage
          }else{
            if(this.pageNo-Math.floor(this.continues/2)>1){
               start=this.pageNo-Math.floor(this.continues/2)
            }else{
               end=this.continues;
               start=1;
            };
        
            if(this.pageNo+Math.floor(this.continues/2)<this.totalPage&&end==0){
                end=this.pageNo+Math.floor(this.continues/2)
            }else{
              if(end==0){
                end=this.totalPage;
                start=this.totalPage-4
              }
               
            }
          }
          
          return {start,end}
        }
      }
      
    }
  </script>
  
  <style lang="less" scoped>
    .pagination {
      text-align: center;
      button {
        margin: 0 5px;
        background-color: #f4f4f5;
        color: #606266;
        outline: none;
        border-radius: 2px;
        padding: 0 4px;
        vertical-align: top;
        display: inline-block;
        font-size: 13px;
        min-width: 35.5px;
        height: 28px;
        line-height: 28px;
        cursor: pointer;
        box-sizing: border-box;
        text-align: center;
        border: 0;
  
        &[disabled] {
          color: #c0c4cc;
          cursor: not-allowed;
        }
  
        &.active {
          cursor: not-allowed;
          background-color: #ff6640;
          color: #fff;
        }
      }
    }

  </style>